Blue Tank?

Just been in a battle and one of the tanks on my team was BLUE. Im not talking about the dark blue that Tank destroyers are, I also know that normal tanks are grey and artillery are brown but this tank was BRIGHT BLUE and the player name was blue as well. Someone on the team proceeded to team kill this tank right away at the start of the match.

What was this blue tank?

Is it some form of special event tank?

Was it a gamemaster having a lil fun if there are even game masters in this?

Having never seen one before and being quite new to the game I would like to know what this was.

Don't kill them if they haven't done anything wrong though. Last battle i played our T-50-2 was slowly killing our T95 from behind, so our E-100 killed him and went blue. Then others on our team started to shoot him even though he was just saving our T95, so he killed them too. The last part may have been an overreaction on his part as he only had 3% damage done to him and ended up with 3 TKs.

most TKs are usualyl made by idiots that would rather spoil everyone else's game than learn to play, like I've seen a lot of tier 5 taks starting to teamkill probabyl because they were in a tier 9 battle

I must be alone in not killing 'blue's.
We don't know what drove them to TKing in a previous game. Maybe he had good reason(for him), to resort to
such tactics.
But I do know that if a team member kills a 'blue', we are down one tank already.
However, if the dipstick then proceeds to shoot up fellow team members, i'll finish him quickly.

We dont know what they did to achieve blue status, however if it is blue it means he did a lot of team damage (by accident or on pourpose).

For me it is a warnning "Watch out for this player, he may cause some troubles". If he plays normally i dont do anything i dont do anything against him. But if he starts doing some stupid things - well...

team killer is blue.....other members of the team can kill the team killer when he has turned blue without punishment.

Annoyingly, that doesn't always work.

I was in my KV-1 and some nit in a T3 tank TK'd someone on our team. At first no one did anything, other than the victim being understandably ticked. Then the little twit ground up against the back of my KV and started trying to push. Good luck with that, obviously. He was already blue by this point. And then, suicidally, he started shooting me. I told him to quit it. He kept going. He wasn't doing any damage, mark you, but he was blue and I had lost my patience.

I turned around, aimed, BAM. Nearly dead, aim, BAM. Smouldering scrap pile. Typical spew of self righteous venom and all that. We went on to win.
And, despite him being blue, I still got fined. So, uh....wut? Why did that happen? He was inescapably bright blue.